is there any form of amateur motorsports which has retained, or increased their participation?
I think the crux of the issue is that people’s interests aren’t what they once were – for better or worse. The other issue is that the smaller the middle class becomes, the smaller those interested in karting become.
I don’t think it’s become too technical – fragmented, perhaps. Karts are still just a steel chassis with no suspension and a basic carburetor stuck to a dirt-simple engine.
With that said: yes, people who understand how to optimize those things – through more advanced technology – will always have an advantage, regardless of the simplicity.